Bipolar disorders

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Letter to the Editor

Editor, – There are significant problems with the use of literature to support the statements in the article by Dr Singh and Professor Berk on acute management of bipolar disorders (Aust Prescr 2008;31:73-6). The authors have generalised from bipolar I disorder to bipolar II disorder and from severely ill tertiary-treated bipolar I patients to the broader population of patients with bipolar disorder. They have also misrepresented the risk of suicide and the relationship between medication status and relapse risk.

According to the article, 'sufferers spend 32-50% of follow-up in depressive states and only 1-9% in elevated states'. However, the source cited focused on bipolar I disorder and cautioned that 'Generalization to other samples of BP-I may be limited because the CDS cohort consisted of severely ill, tertiary care, white patients'.1Inappropriately generalising biased samples contributes to the clinician's illusion2, which distorts perceptions of chronicity and severity.

The article claimed that over 90% of patients with bipolar disorders relapse without medications. However, in the source cited the relapse rate applied specifically to bipolar I disorder.3The implication that relapse occurs only without medication ignores a large body of evidence that it frequently occurs with medication.4,5,6,7The use of psychotropic drugs between episodes is not associated with time to relapse or recurrence.8

The statement that 15% of people with bipolar disorders die by suicide is based on pharmaceutical industry funded grey literature.9Australian empirical evidence was lacking in this citation and relied on an article by Goodwin and Jamison.10Later, Jamison acknowledged that the quoted risk of 15% may have been too high.11The inflated risk was based largely on inpatient samples, inappropriately generalised to the broader population.

The article largely ignored the value of psychological interventions. There is strong evidence that these are effective in the prevention of relapse. Despite emphasising the destabilisation potential of antidepressants, the authors do not mention the potential adverse effects of antipsychotics and other drugs for bipolar episodes. These include obesity, diabetes, metabolic syndrome and dyslipidaemia.12

These problems with the article exaggerate both the severity of bipolar disorders and the value of medications, while devaluing psychological treatments.

Authors' comments

Several issues are raised by the reader's correspondence. It needs to be stressed that the paper is based on the available, if imperfect, evidence base. Firstly, the validity of suicide risk estimates in bipolar disorders has been raised. A meta-analysis of studies on suicide risk in all psychiatric disorders found that the risk of suicide was about 15-fold for patients with index diagnosis bipolar disorder.13In a 1-9 year follow-up study, 6% of bipolar I and 18% of bipolar II patients died by suicide.14Based on six independent studies, the rate of suicide attempts is reported as 17% for bipolar I disorder and 24% for bipolar II disorder.15Despite varying rates in the literature, the risk of suicide and self-harm in bipolar disorders is the major driver of mortality in the disorder, and needs to be one of the critical foci of treatment.

Secondly, while psycho education and cognitive behavioural therapy have an important place in relapse prevention in the maintenance phase, they have not been studied in the acute treatment of either mania or depression, and while we agree that they are of potential value, the absence of an evidence base precludes their inclusion in an evidence-based summary. Clinical trials of psychosocial treatments in the acute phase of the disorder, particularly in depression, are clearly a priority, given the limitations of available treatments.16,17While healthy skepticism has an important role in evidence-based medicine, it is still necessary to be guided by the available data.

Dr Ajeet Singh

Professor Michael Berk

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